The percentage of carotene to the total vitamin A taken by Japanese people, is reported about 95%. It is very important problem, therefore, how carotene is utilized in human bodies. In various investigations, the carotene level in blood has been of much interest in the stage of carotene absorption in its metabolic process. In this experiment, the petroleum ether extracts gained from serum of cattle and human being were isolated by chromatography with alimina and investigated. In case of serum of cattle, β-carotene occupied almost 90% of the pigments in the petroleum ether extracts, while in case of human blood, it was only from 20 to 30% of the carotenoids pigments as shown in the table 2.
Vitamin A and carotene contents of serum were estimated by Bessey's method for 47 healthy men aged from 20 to 30 year vitamin A contents gained from about 80% of total subjects were 10-39.9γ/dl, on the other hand, carotene contents gained from 30% of the total were 30-39.9γ/dl, and the average values were 25.5±11.3γ/dl and 56.3±27.4γ/dl respectively. This results showed that the vitamin A level of serum was some what low, and carotene level is distributed in more wide range than the vitamin A which held almost constant value.